Tool magazine having grips capable of maintaining tool gripping force regardless of orientation of magazine disk

Abstract

A tool magazine having a plurality of grips for gripping tool holders for use in a machine tool. The tool holder gripped at the grip is transferred to a holder portion of a spindle of a machine tool, or the tool holder held in the holder portion is transferred to the grip. The magazine has a magazine disk rotatable about a horizontal axis for tool indexing operation. The tool holder extends in the horizontal direction when it is gripped by the grip, and the spindle also extends in the horizontal direction. Each grip includes a pair of first and second arm members pivotally supported on the magazine disk and extending in a radial direction of the magazine disk. The first and second arm members has tool gripping portions movable toward and away from each other for gripping and releasing the tool holder. A compression spring is provided between the pair of first and second arm members for normally urging the first and second arm members to their tool gripping positions. First and second gear portions are provided in meshing relation to the first and second arm members, respectively. If lower side arm member is moved by the weight of the tool holder, the upper side arm member is moved interlockingly and symmetrically to compress the compression spring.

What is claimed is: 
     
       1. A tool magazine for accommodating a plurality of tools and transferring a selected one of the tools with respect to a spindle of a machine tool, the tool magazine comprising: a magazine disk rotatable about a horizontal axis;   at least one grip comprising a pair of first and second arm members pivotally supported on the magazine disk and extending in a radial direction of the magazine disk, the first and second arm members having tool gripping portions movable toward and away from each other for gripping and releasing the tool by the pivotal movement of the arm members;   a biasing member provided between the pair of first and second arm members for normally urging the first and second arm members to their tool gripping positions; and   interlocking means provided at the first and second arm members for pivotally and symmetrically moving one of the first and second arm members interlockingly with pivotal movement of the remaining one of the second and first arm members.   
     
     
       2. The tool magazine as claimed in claim 1, wherein the interlocking means comprises pair of first and second gear portions meshedly engaged with each other, the first gear portion being provided at the first arm member and the second gear portion being provided at the second arm member. 
     
     
       3. The tool magazine as claimed in claim 2, wherein each first and second arm member has an intermediate portion pivotally supported at the magazine disk, each first and second arm members having a radially outer portion, a radially outer end, a radially inner portion and a radially inner end with respect to the intermediate portion, the tool gripping portions of the first and second arm members being provided at confronting surfaces of the radially outer portions, and wherein the biasing member is interposed between confronting surfaces of the radially inner portions of the first and second arm members. 
     
     
       4. The tool magazine as claimed in claim 3, wherein rotation axes of the first and second gears are on longitudinal axes of the first and second arm members. 
     
     
       5. The tool magazine as claimed in claim 4, further comprising a lock pin movable in an axial direction thereof, the radially inner ends of the first and second arm members being abutable on the lock pin when the lock pin is moved to a first position for preventing the radially outer ends of the first and second arm members from moving away from each other, the radially inner ends being out of contact with the lock pin when the lock pin is moved to a second position for allowing one of the radially outer ends of the first and second arm members to move away from the other. 
     
     
       6. The tool magazine as claimed in claim 5, further comprising rollers each provided rotatably at the radially outer end of the arm member. 
     
     
       7. The tool magazine as claimed in claim 5, further comprising a pair of projections projecting from the confronting surfaces of the radially inner portions of the arm members toward each other, and wherein the biasing member comprises a compression coil spring having two ends, one end of the compression spring being seated on one of the projections and the other end of the compression spring being seated on the other projection. 
     
     
       8. A machine tool comprising: a column movable in two dimensional directions in a horizontal plane;   a spindle head movable in a vertical direction;   a spindle supported in the spindle head and having a tool holder portion;   a tool magazine rotatably supported by the column and having at least one grip for accommodating at least one tool and for transferring a tool between the tool holder portion and the grip, the tool magazine comprising: a magazine disk rotatable about a horizontal axis;   the at least one grip comprising a pair of first and second arm members pivotally supported on the magazine disk and extending in a radial direction of the magazine disk, the first and second arm members having tool gripping portions movable toward and away from each other for gripping and releasing the tool by the pivotal movement of the arm members;   a biasing member provided between the pair of first and second arm members for normally urging the first and second arm members to their tool gripping positions; and   interlocking means provided at the first and second arm members for pivotally moving one of the first and second arm members interlockingly with pivotal movement of the remaining one of the second and first arm members.     
     
     
       9. The machine tool as claimed in claim 8, wherein the interlocking means comprises a pair of first and second gear portions meshedly engaged with each other, the first gear portion being provided at the first arm member and the second gear portion being provided at the second arm member. 
     
     
       10. The machine tool as claimed in claim 9, wherein each first and second arm member has an intermediate portion pivotally supported at the magazine disk, each first and second arm members having a radially outer portion, a radially outer end, a radially inner portion and a radially inner end with respect to the intermediate portion, the tool gripping portions of the first and second arm members being provided at confronting surfaces of the radially outer portions, and wherein the biasing member is interposed between confronting surfaces of the radially inner portions of the first and second arm members. 
     
     
       11. The machine tool as claimed in claim 10, wherein rotation axes of the first and second gears are on longitudinal axes of the first and second arm members. 
     
     
       12. The machine tool as claimed in claim 11, further comprising a lock pin movable in an axial direction thereof, the radially inner ends of the first and second arm members being abuttable on the lock pin when the lock pin is moved to a first position for preventing the radially outer ends of the first and second arm members from moving away from each other, the radially inner ends being out of contact with the lock pin when the lock pin is moved to a second position for allowing one of the radially outer ends of the first and second arm members to move away from the other. 
     
     
       13. The machine tool as claimed in claim 12, further comprising rollers each provided rotatably at the radially outer end of the arm member. 
     
     
       14. The tool magazine as claimed in claim 13, further comprising a pair of projections projecting from the confronting surfaces of the radially inner portions of the arm members toward each other, and wherein the biasing member comprises a compression coil spring having two ends, one end of the compression spring being seated on one of the projections and the other end of the compression spring being seated on the other projection.